I suggest you ...

Give more control over all-day events when changing time zones

With the previous version of Sync2, all-day events (in at least one of the calendars) are treated as Midnight to Midnight in a particular time zone. When traveling and changing time zones the events "walk" into the previous or next day. I've had repeating annual events such as holidays or birthdays end up on three separate days. This is tricky but needs some control to define the desired behavior. I had to turn off Sync2 finally to stop this damage to the calendars.